The present invention relates to an assembly for preparing and dispensing a solution as well as to a stopper for this assembly, and to the process for manufacturing the stopper.
Such an assembly is generally presented to the user in extemporaneous form, i.e. to be prepared at the moment of use.
A first bottle contains the solvent and a second bottle contains the substance to be dissolved, for example in lyophilized form; this substance may also be in liquid form, the solution then being prepared by mixing the two liquid components at the moment of use.
To prepare the solution, the user opens the two bottles, pours the solvent into the second bottle containing the substance to be dissolved, stoppers the latter before stirring it in order to complete dissolution or mixture of the two components.
This manipulation is not always easy, as the bottles are often of small dimensions. A certain skill is necessary and there is always a risk of spilling part of the solvent when the user pours said solvent into the second bottle and when he stoppers the latter, particularly in the case of such stoppering being effected by means of a teat for instillation which is often difficult to fit on the bottle.
In addition, as both bottles must be opened, there are also risks of contamination from the user's fingers during preparation or when stoppering the second bottle; it is therefore impossible to guarantee that the preparation made in this manner is perfectly sterile.
It is one of the objects of the present invention to overcome these drawbacks by proposing an assembly allowing the sterile preparation of the solution. In fact, the assembly according to the invention does not require that the bottles be opened.
To this end, the assembly according to the invention comprises:
a first bottle containing the first liquid component, of which the neck terminates in an elongated head traversed by a longitudinal conduit placing the interior of the bottle in communication with the outside,
a second bottle containing the second component, liquid or solid,
a stopper for this second bottle, presenting on its outer face a recess whose shape is homologous of that of the head of the first bottle, and of which the bottom is separated from the interior of the second bottle only by a thin membrane of elastically deformable material,
this membrane further having an axial orifice passing therethrough, which is hermetically closed, in the absence of deformation of the membrane, by the natural radial constriction of the material constituting the membrane,
the penetration of the head of the first bottle into the recess of the stopper producing an axial deformation of the membrane and a radial distension of the orifice opening a passage for a liquid through the membrane, so that this passage allows a transfer of liquid from one bottle into the other after these two bottles have been joined together,
means further being provided to produce a differential pressure between the atmospheres of the two bottles to force the transfer, into the second bottle, of the liquid contained in the first bottle.
The recess in the stopper is advantageously provided with an inner thread, the head of the first bottle being provided with a homologous outer thread, to allow the two bottles to be joined by screwing.
In a variant embodiment, the recess in the stopper may be a cylindrical recess of radial dimensions slightly less than the radial dimensions of the head, which is cylindrical, of the first bottle, the penetration of the head of the first bottle into the stopper producing a radial deformation of the stopper, ensuring clamping thereof on the head of the first bottle to allow the two bottles to be joined.
The axial orifice of the obturator is preferably formed by pre-boring the membrane, without removal of matter. This pre-boring may for example be effected by penetration through the membrane of a solid needle, during a stamping step when the stopper is being manufactured.
The stopper advantageously possesses a substantially flat upper stop surface, the head of the first bottle extending, in projection above a shoulder of the neck of this bottle, over a height greater than the depth of the recess with respect to the upper surface of the stopper, the axial deformation of the membrane being limited by the shoulder of the neck of the first bottle coming into abutment against the upper surface of the stopper of the second bottle.
The assembly may be made according to a first embodiment, in which the differential pressure between the atmospheres of the two bottles is produced by outside compression of the wall of the first bottle, the latter being made of a deformable material.
In a second embodiment, the differential pressure between the atmospheres of the two bottles results from a vacuum made inside the second bottle, the latter being made of a rigid material.
In a third embodiment, the first bottle presents a generally cylindrical, rigid body in which slides a piston mobile under the effect of outside ation so as to create the differential pressure necessary to force the transfer of liquid from one bottle into the other.